Tritertbutyl aluminum reactants for vapor deposition

ABSTRACT

Aluminum (Al) hydrocarbon precursor compositions are provided that can be used for vapor deposition of transition metal carbide thin films, for example aluminum-doped transition metal carbide thin films such as Al-doped titanium carbide thin films. In some embodiments, the precursor compositions comprise one or more isomers of tritertbutyl aluminum (TTBA). In some embodiments the precursor compositions comprise at least 50% of Isomer 1 of TTBA, at least 50% of Isomer 2 of TTBA, or at least 20% of a combination of Isomer 1 and Isomer 2, where Isomer 1 has the formula Al(tert-Bu) 2 (iso-Bu) and Isomer 2 has the formula Al(tert-Bu)(iso-Bu) 2 . A container containing a precursor composition comprising at least 50% of Isomer 1 or Isomer 2 or at least 20% of a combination of Isomer 1 and 2 of TTBA can be attached to a vapor deposition reactor and used to deposit transition metal carbide thin films such as Al-doped titanium carbide thin films by atomic layer deposition or chemical vapor deposition.

BACKGROUND

Field of the Invention

The present application relates generally to reactants comprisingisomers of tritertbutyl aluminum (TTBA) and their use in vapordeposition processes, such as in the deposition of transition metalcarbide thin films, for example aluminum-doped titanium carbide thinfilms.

Description of the Related Art

Metal carbides, such as titanium carbides, have found use in variousapplications in the electronics industry, from gate electrodes todiffusion barriers. Metal carbide thin films have been formed by variousmethods including chemical vapor deposition (CVD), physical vapordeposition (PVD) and atomic layer deposition (ALD).

Metal halide reactants have been used in combination with aluminumprecursors such as trimethyl aluminum (TMA) and triethyl aluminum (TEA)to deposit metal carbide thin films.

SUMMARY

In some embodiments, methods of depositing aluminum-doped transitionmetal carbide thin films on a substrate in a reaction space areprovided. The methods may comprise contacting the substrate with a firstvapor phase reactant formed by vaporizing a first precursor compositioncomprising Isomer 1 and/or Isomer 2 of tritertbutyl aluminum (TTBA),wherein the Isomer 1 has a formula Al(tert-Bu)₂(iso-Bu) and the Isomer 2has a formula Al(tert-Bu)(iso-Bu)₂, and a second vapor phase reactantformed by vaporizing a second precursor comprising a transition metalhalide.

In some embodiments, the method is a chemical vapor deposition process.In some embodiments, the method is an atomic layer deposition process.

In some embodiments, methods comprise at least one deposition cycle inwhich the substrate is alternately and sequentially contacted with thefirst vapor phase reactant comprising TTBA Isomer 1 and/or Isomer 2 anda second vapor phase transition metal halide reactant. In someembodiments, the deposition cycle is repeated two or more times.

In some embodiments, the methods comprise contacting the substrate witha vapor phase titanium precursor, wherein the titanium precursorcomprises a titanium halide, for example, TiCl₄.

In some embodiments, the first precursor composition comprises at least50% Isomer 1. In some embodiments, the first precursor compositioncomprises at least 80% Isomer 1. In some embodiments, the firstprecursor composition comprises at least 90% Isomer 1.

In some embodiments, the first precursor composition comprises at least50% Isomer 2. In some embodiments, the first precursor compositioncomprises at least 80% Isomer 2. In some embodiments, the firstprecursor composition comprises at least 90% Isomer 2.

In some embodiments the first precursor composition comprises bothIsomer 1 and Isomer 2. In some embodiments, the first precursorcomposition comprises at least 20% of a combination of Isomer 1 andIsomer 2. That is, the percentage of Isomer 1 in the composition plusthe percentage of Isomer 2 in the composition is greater than 20%. Insome embodiments, the first precursor composition comprises at least 50%of a combination of Isomer 1 and Isomer 2. That is, the percentage ofIsomer 1 in the composition plus the percentage of Isomer 2 in thecomposition is greater than 50%. In other embodiments, the firstprecursor composition comprises at least 80% of a combination of Isomer1 and Isomer 2. That is, the percentage of Isomer 1 in the compositionplus the percentage of Isomer 2 in the composition is greater than 80%.

In some embodiments, the first precursor composition does not compriseTTBA or Isomer 3. In some embodiments, the first precursor compositionmay comprise small or trace quantities of Isomer 3. For example, in someembodiments the first precursor composition may comprise at most 5%Isomer 3. In some embodiment, the first precursor composition maycomprise small or trace quantities of TTBA. For example, in someembodiments the first precursor composition may comprise at most 5%TTBA. In some embodiments the first precursor composition may comprisesmall or trace quantities of both TTBA and Isomer 3, such as up to atmost 5% of each.

In some embodiments, a vapor deposition precursor composition comprisinggreater than 50% Isomer 1, greater than 50% Isomer 2, or greater than20% of a combination of Isomer 1 and 2 of Al(tert-Bu)₃ is provided,wherein Isomer 1 has the formula Al(tert-Bu)₂(iso-Bu) and Isomer 2 hasthe formula Al(tert-Bu)(iso-Bu)₂. In some embodiments, the compositioncomprises greater than 70% Isomer 1. In some embodiments, thecomposition comprises greater than 80% Isomer 1. In some embodiments,the composition comprises greater than 70% Isomer 2. In someembodiments, the composition comprises greater than 80% Isomer 2. Insome embodiments, the composition additionally comprises Al(tert-Bu)₃.In some embodiments, the composition additionally comprises Isomer 3 ofAl(tert-Bu)₃, wherein Isomer 3 has the formula Al(iso-Bu)₃.

In some embodiments, the vapor deposition precursor compositioncomprises at least 20% of Isomer 1 and Isomer 2 taken together. In someembodiments, the vapor deposition precursor composition comprises atleast 50% of Isomer 1 and Isomer 2 taken together. In some embodiments,the vapor deposition precursor composition comprises at least 80% ofIsomer 1 and Isomer 2 taken together. In some embodiments, the vapordeposition precursor composition comprises Isomer 1 and Isomer 2 anddoes not comprise Isomer 3. In some embodiments, the vapor depositionprecursor composition comprises Isomer 1 and Isomer 2 and at most 5%Isomer 3

In some embodiments, a container configured to be attached to adeposition reactor is provided, with the container containing acomposition comprising at least 50% Isomer 1 or at least 50% Isomer 2 ofAl(tert-Bu)₃, wherein Isomer 1 has the formula Al(tert-Bu)₂(iso-Bu) andIsomer 2 has the formula Al(tert-Bu)(iso-Bu)₂. In some embodiments, thecomposition comprises greater than 70% Isomer 1. In some embodiments,the composition comprises greater than 80% Isomer 1. In someembodiments, the composition comprises greater than 70% Isomer 2. Insome embodiments, the composition comprises greater than 80% Isomer 2.In some embodiments, the composition additionally comprisesAl(tert-Bu)₃. In some embodiments, the composition additionallycomprises Isomer 3 of Al(tert-Bu)₃, wherein Isomer 3 has the formulaAl(iso-Bu)₃.

In some embodiments, a container configured to be attached to adeposition reactor is provided, with the container containing acomposition comprising at least 20% of a combination of Isomer 1 andIsomer 2. In some embodiments, the composition comprises at least 50% ofa combination of Isomer 1 and Isomer 2. In some embodiments, thecomposition comprises at least 80% of a combination of Isomer 1 andIsomer 2. In some embodiments, the composition comprises a combinationof Isomer 1 and Isomer 2 and does not comprise Isomer 3. In someembodiments, the composition comprises a combination of Isomer 1 andIsomer 2 and at most 5% Isomer 3

In some embodiments, a deposition reactor is provided comprising a firstreactant container fluidly connected to a reaction chamber, the reactantcontainer comprising a first precursor composition comprising at least50% of an isomer of Al(tert-Bu)₃, wherein the isomer of Al(tert-Bu)₃ isIsomer 1 of formula Al(tert-Bu)₂(iso-Bu) or Isomer 2 of formulaAl(tert-Bu)(iso-Bu)₂ In some embodiments, the first reactant containercomprises a precursor composition comprising at least 20% of acombination of Isomer 1 and Isomer 2. In some embodiments, the firstreactant container comprises a precursor composition comprising at least50% of a combination of Isomer 1 and Isomer 2. In some embodiments, thefirst reactant container comprises a precursor composition comprising atleast 80% of a combination of Isomer 1 and Isomer 2. In someembodiments, the reactant container does not comprise Isomer 3. In someembodiments, the reactant container may comprise at most 5% Isomer 3. Insome embodiments the reactant container does not comprise TTBA. In someembodiments, the reactant container may comprise at most 5% TBBA.

In some embodiments, the deposition reactor is configured to vaporizethe first precursor composition and conduct the vapor to the reactionchamber.

In some embodiments, the deposition reactor comprises a second reactantcontainer, the second container comprising a transition metal halideprecursor composition such as titanium halide precursor composition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the isomerization of tritertbutyl aluminum (TTBA) intoIsomer 1, Isomer 2 and Isomer 3.

DETAILED DESCRIPTION

Transition metal carbide thin films, such as titanium carbide (TiC) thinfilms and aluminum-doped transition metal carbide thin films such astitanium aluminum carbide (TiAlC) thin films can be used in a variety ofcontexts, including metal gate and gate electrode applications in metaloxide semiconductor field effect transistors (MOSFETs), such asn-channel MOSFETs (NMOS). Transition metal carbide thin films andaluminum-doped transition metal carbide thin films, such as TiC andTiAlC thin films, with desirable properties can be formed by employingaluminum hydrocarbon compounds to carburize a metal (e.g., titanium(Ti)) reactant on a substrate. While such films have been deposited byvapor deposition using titanium halide precursors in combination withaluminum reactants such as trimethyl aluminum (TMA) and triethylaluminum (TEA), it has been found that films deposited using aluminumreactants that do not comprise beta hydrogens can have improvedproperties. Transition metal carbide thin films and aluminum-dopedtransition metal carbide thin films, such as Al-doped TiC thin films,can be deposited using tritertbutyl aluminum (TTBA) precursorcompositions. These reactants can be used to produce thin films withimproved properties, such as lower resistivity and/or lower workfunction, relative to films deposited using a titanium halide and TMA orTEA.

However, TTBA has been found to be susceptible to isomerization overtime, such as under typical storage conditions. This isomerization canlead to variability in the quality of the films deposited using the TTBAreactant. This variability can be controlled by utilizing TTBAcompositions that comprise one or more of the three TTBA isomers. Thus,as discussed in more detail below, in some embodiments TTBA compositionscomprising one or more TTBA isomers are provided. As discussed below, insome embodiments the TTBA compositions may comprise one or more isomersof TTBA but not TTBA itself. The TTBA compositions can be used asreactants in vapor deposition processes, such as in ALD and CVDprocesses for depositing transition metal carbide thin films, and inparticular Al-doped transition metal carbide thin films such as Al-dopedTiC thin films.

Using the methods and compositions described herein, transition metalcarbide thin films with an increased aluminum content and/or desirablecharacteristics such as low resistivity can be formed on a substrate. Asubstrate in a reaction space is contacted with a vapor phase titaniumsource chemical, such as a titanium halide, and a reactant comprisingone or more TTBA isomers as described below. The films preferably havegood adhesion, low resistivity and good oxidation resistance. Thereaction conditions, such as the reaction temperature, pressure, pulseand purge times, pulsing sequence and post deposition annealing can alsobe adjusted to achieve films with the desired properties.

In some embodiments, transition metal carbide thin films such asAl-doped TiC thin films are formed over a substrate in an ALD-typeprocess by alternately and sequentially contacting the substrate with atransition metal compound, such as a transition metal halide, and areactant comprising one or more TTBA isomers formed by vaporizing aprecursor composition as described herein. In some embodiments analuminum-doped titanium carbide film is formed on a substrate by anALD-type process by alternately and sequentially contacting thesubstrate with a titanium compound, preferably a titanium halide, and areactant comprising one or more TTBA isomers as described herein.

By using a reactant comprising one or more TTBA isomers and appropriatereaction conditions, a transition metal carbide film and in particularan Al-doped transition metal carbide thin films such as Al-doped TiCthin films with properties that are advantageous to a particularsituation can be formed. For example, in some embodiments, a film withlow resistivity is formed using a precursor composition as describedherein. In some embodiments, metal carbide films, such as Al-dopedtitanium carbide films having a resistivity of about 4.60 eV to about4.20 eV are deposited. In some embodiments, films with an aluminumconcentration of about 1% to about 30%, more preferably about 6% toabout 16% are deposited.

Compositions

In some embodiments, compositions comprising one or more TTBA isomersare provided that can be used for forming transition metal carbidefilms, and in particular Al-doped transition metal carbide thin filmssuch as Al-doped titanium carbide thin films by vapor depositionprocesses such as ALD or CVD. The compositions can be vaporized such asby heating and the reactant vapor provided to a reaction space asdiscussed in more detail below. The vaporized composition may bereferred to herein as a TTBA reactant. Although described primarily interms of Al-doped transition metal carbide thin film deposition, such astitanium carbide and/or titanium aluminum carbide thin film deposition,other types of thin films may be deposited using the disclosedcompositions.

Tritertbutyl aluminum (TTBA) has the formula C₁₂H₂₇Al (IUPACname—tris(2-methyl-2-propanyl)aluminum), and can be described asAl((tert-Bu)₃). As mentioned above, TTBA has been found to spontaneouslyisomerize under certain conditions and therefore can be unstable duringstorage and use. For example, when stored for long periods (e.g., oneyear) at room temperature, or when stored for shorter periods (e.g.,days or weeks) at higher temperatures (e.g., when subjected to heat over60° C.) a TTBA composition may undergo isomerization such that thenature of the composition changes over time. TTBA degrades over timeinto a mixture of TTBA and one or more of its three isomers. Theisomerization of TTBA into its three isomers is illustrated in FIG. 1.This isomerization can lead to variability over time in the quality ofthin films deposited using a TTBA source.

As illustrated in FIG. 1, TTBA has at least three isomers, referred toherein as Isomer 1, Isomer 2 and Isomer 3. Isomer 1 (IUPACname—bis(2-methyl-2-propanyl)-(2-methyl-1-propanyl)aluminum) has theformula Al(tert-Bu)₂(iso-Bu), Isomer 2 (IUPAC name-(2-methyl-2-propanyl)-bis(2-methyl-1-propanyl)aluminum) has the formulaAl(tert-Bu)(iso-Bu)₂ and Isomer 3 (IUPACname—tris(2-methyl-1-propanyl)aluminum) has the formula Al(iso-Bu)₃.Without wishing to be held to any theory, it is believed that TTBA canisomerize to Isomer 1 at room temperature or at higher temperatures(e.g., 60° C.) and that isomerization of TTBA to Isomer 1 occursrelatively easily, whereas isomerization to Isomer 2 and Isomer 3 isrelatively more difficult and progressively harder. For example, Isomer1 is relatively stable at ≦50° C. and at ≦50° C. Isomer 1 does notsignificantly further isomerize into Isomer 2 and Isomer 3. However,Isomer 1 can isomerize to Isomer 2 at least at about 80° C.

Accordingly, a composition comprising a larger percentage of Isomer 1can be more stable over time at typical temperatures used for storageand in vapor deposition reactors than compositions comprising a greaterpercentage of TTBA. Thus, in some embodiments, a precursor compositionis provided comprising at least 50% Isomer 1, at least 70% Isomer 1, atleast 80% Isomer 1, at least 90% Isomer 1, at least 95% Isomer 1 or atleast 99% Isomer 1. As used herein, the recited percentage compositionof the precursors is determined by percentage mass.

In some embodiments, a precursor composition comprises a mixture of TTBAand Isomer 1. In some embodiments, Isomer 1 makes up at least 50% of theTTBA precursor composition. In some embodiments Isomer 1 makes up atleast 70% of the TTBA precursor composition. In some embodiments, Isomer1 comprises at least 70, 75, 80, 85, 90, 91, 92, 93, 94 or 95% of theTTBA precursor composition.

In some embodiments the TTBA precursor composition does not compriseIsomer 2. In some embodiments the TTBA precursor composition does notcomprise Isomer 3. In some embodiments the TTBA precursor compositionmay comprise at most about 5% Isomer 3.

In some embodiments a precursor composition comprising Isomer 1 does notcomprise TTBA. In some such embodiments, an Isomer 1 precursorcomposition is provided in which Isomer 1 makes up at least 50% of theprecursor composition. In some embodiments an Isomer 1 precursorcomposition is provided in which Isomer 1 makes up at least 70% of theprecursor composition. In some embodiments, an Isomer 1 precursorcomposition is provided in which Isomer 1 comprises at least 70, 75, 80,85, 90, 91, 92, 93, 94 or 95% of the precursor composition. In someembodiments the Isomer 1 precursor composition does not comprise Isomer2. In some embodiments the Isomer 1 precursor composition does notcomprise Isomer 3. In some embodiments the Isomer 1 precursorcomposition may comprise at most about 5% Isomer 3.

In some embodiments, a TTBA precursor composition may comprise Isomers 2and/or 3 in addition to TTBA and Isomer 1. Thus, in some embodiments, aTTBA precursor composition comprises TTBA, Isomer 1 and may additionallycomprise Isomer 2. For example, as disclosed herein a precursorcomposition may comprise TTBA and at least 20% of a combination ofIsomer 1 and Isomer 2. In some embodiments, the TTBA precursorcomposition comprises TTBA, Isomer 1 and may additionally compriseIsomers 2and 3. In some embodiments, the total amount of Isomer 2 andIsomer 3 in the composition is less than about 30%, less than about 20%,less than about 10%, less than about 5%, or less than about 1%.

In some embodiments, a precursor composition is provided comprising atleast 50% Isomer 2, at least 70% Isomer 2, at least 80% Isomer 2, atleast 90% Isomer 2, at least 95% Isomer 2 or at least 99% Isomer 2.

In some embodiments, a TTBA precursor composition comprises a mixture ofTTBA and Isomer 2. In some embodiments, Isomer 2 makes up at least 50%of the TTBA precursor composition. In some embodiments Isomer 2 makes upat least 70% of the TTBA precursor composition. In some embodiments,Isomer 2 comprises at least 70, 75, 80, 85, 90, 91, 92, 93, 94 or 95% ofthe TTBA precursor composition.

In some embodiments a precursor composition comprising Isomer 2 does notcomprise TTBA. In some such embodiments, an Isomer 2 precursorcomposition is provided in which Isomer 2 makes up at least 50% of theprecursor composition. In some embodiments an Isomer 2 precursorcomposition is provided in which Isomer 2 makes up at least 70% of theprecursor composition. In some embodiments, an Isomer 2 precursorcomposition is provided in which Isomer 2 comprises at least 70, 75, 80,85, 90, 91, 92, 93, 94 or 95% of the precursor composition. In someembodiments the Isomer 2 precursor composition does not compriseIsomer 1. In some embodiments the Isomer 2 precursor composition doesnot comprise Isomer 3. In some embodiments the Isomer 2 precursorcomposition may comprise at most about 5% Isomer 3.

In some embodiments, a TTBA precursor composition may comprise Isomers 1and/or 3 in addition to TTBA and Isomer 2. Thus, in some embodiments, aTTBA precursor composition comprises TTBA, Isomer 1 and may additionallycomprise Isomer 2. In some embodiments, the TTBA precursor compositioncomprises TTBA, Isomer 2 and may additionally comprise Isomers 1 and 3.In some embodiments, the total amount of Isomer 1 and Isomer 3 in thecomposition is less than about 30%, less than about 20%, less than about10%, less than about 5%, or less than about 1%.

In some embodiments, a precursor composition may comprise at least 20%of a combination of Isomer 1 and Isomer 2. That is, the percentage ofIsomer 1 plus the percentage of Isomer 2 in the composition is greaterthan 20%. In some embodiments the precursor composition may compriseTTBA and at least 20% of a combination of Isomer 1 and Isomer 2. In someembodiments, a precursor composition may comprise at least 50% of acombination of Isomer 1 and Isomer 2. That is, the percentage of Isomer1 plus the percentage of Isomer 2 in the composition is greater than50%. In some embodiments a TTBA precursor may comprise TTBA and at least50% of a combination of Isomer 1 and Isomer 2. In some embodiments, aprecursor composition may comprise at least 80% of a combination ofIsomer 1 and Isomer 2. That is, the percentage of Isomer 1 plus thepercentage of Isomer 2 in the composition is greater than 80%. In someembodiments a TTBA precursor may comprise TTBA and at least 80% of acombination of Isomer 1 and Isomer 2. In some embodiments, a TTBAprecursor composition comprises a combination of Isomer 1 and Isomer 2and does not comprise Isomer 3.

In some embodiments, a precursor composition comprises a combination ofIsomer 1 and Isomer 2 and a trace percentage of Isomer 3. For example, aprecursor composition may comprise a combination of Isomer 1 and Isomer2 and at most 5% Isomer 3. In some embodiments, a TTBA precursorcomprises a combination of Isomer 1 and Isomer 2 and a trace percentageof TTBA. For example, a TTBA precursor may comprise a combination ofIsomer 1 and Isomer 2 and at most 5% TTBA. In some embodiments aprecursor composition may comprise a combination of Isomer 1 and Isomer2, as described above, in addition to at most 5% TTBA and at most 5%Isomer 3.

The term “Isomer 1 precursor composition” is used herein to refer to aprecursor composition comprising at least 50% Isomer 1. As discussedabove, in some embodiments, an Isomer 1 precursor composition maycontain more than 50% of Isomer 1, for example at least 70, 75, 80, 85,90, 91, 92, 93, 94, 95, 98, 99 or 99.5% of Isomer 1. An Isomer 1precursor composition can be vaporized for use in a vapor depositionprocess, and the vapor can be referred to as an “Isomer 1 reactant”.

In some embodiments, an Isomer 1 precursor composition may comprise oneor more additional components, for example TTBA, Isomer 2, Isomer 3and/or contaminants. In some embodiments, the total amount ofcontaminants or minor components is less than about 1% of the precursorcomposition. In some embodiments an Isomer 1 precursor compositioncontains at least a trace amount of TTBA, up to at most 5%. In someembodiments an Isomer 1 precursor composition contains at least a traceamount of Isomer 3, up to at most 5%.

The term “Isomer 2 precursor composition” is used herein to refer to aprecursor composition comprising at least 50% Isomer 2. As discussedabove, in some embodiments, an Isomer 1 precursor composition maycontain more than 50% of Isomer 2, for example at least 70, 75, 80, 85,90, 91, 92, 93, 94, 95, 98, 99 or 99.5% of Isomer 2. An Isomer 2precursor composition can be vaporized for use in a vapor depositionprocess, and the vapor can be referred to as an “Isomer 2 reactant”.

In some embodiments, an Isomer 2 precursor composition may comprise oneor more additional components, for example TTBA, Isomer 1, Isomer 3and/or contaminants. In some embodiments, the total amount ofcontaminants or minor components is less than about 1% of the precursorcomposition. In some embodiments an Isomer 2 precursor compositioncontains at least a trace amount of TTBA, up to at most 5%. In someembodiments an Isomer 2 precursor composition contains at least a traceamount of Isomer 3, up to at most 5%.

The term “Isomer 1 and 2 precursor composition” is used herein to referto a precursor composition comprising at least 20% of a combination ofIsomer 1 and Isomer 2. That is, the percentage of Isomer 1 plus thepercentage of Isomer 2 in the composition is greater than 20%. In someembodiments, an Isomer 1 and 2 precursor composition may contain morethan about 20% of a combination of Isomer 1 and 2, more than about 30%of a combination of Isomer 1 and Isomer 2, more than about 40% of acombination of Isomer 1 and 2, or even more than about 50% of acombination of Isomer 1 and Isomer 2, for example at least 70, 75, 80,85, 90, 91, 92, 93, 94, 95, 98, 99 or 99.5% of a combination of Isomer 1and Isomer 2. An Isomer 1 and 2 precursor composition can be vaporizedfor use in a vapor deposition process, and the vapor can be referred toas an “Isomer 1 and 2 reactant”.

In some embodiments, an Isomer 1 and 2 precursor composition maycomprise one or more additional components, for example TTBA, Isomer 3and/or contaminants. In some embodiments, the total amount ofcontaminants or minor components is less than about 1% of the precursorcomposition. In some embodiments an Isomer 1 and 2 precursor compositioncontains at least a trace amount of TTBA, up to at most 5%. In someembodiments an Isomer 1 and 2 precursor composition contains at least atrace amount of Isomer 3, up to at most 5%.

In some embodiments, an Isomer 1 precursor composition can be preparedby heating a composition consisting essentially of TTBA until a desiredamount of Isomer 1 has formed in the composition. In some embodiments,the composition is heated to form an Isomer 1 precursor composition. Forexample, it can be heated until the composition comprises at least 50%Isomer 1. In some embodiments, the composition is heated at atemperature of about room temperature to about 100° C., preferably about50° C. to about 80° C., more preferably at about 60° C. Isomer 1 maysubsequently be purified to obtain an Isomer 1 precursor compositioncomprising at least about 90%, at least about 95%, at least about 99%,or even at least about 99.5% Isomer 1. In some embodiments, theprecursor composition is heated at a temperature of ≦50° C. until anIsomer 1 precursor composition comprising at least about 50%, at leastabout 60%, at least about 70%, at least about 80%, at least about 90%,at least about 95%, at least about 99%, or even at least about 99.5%Isomer 1 is obtained.

In some embodiments, an Isomer 2 precursor composition can be preparedby heating a composition consisting essentially of TTBA until a desiredamount of Isomer 2 has formed in the composition. In some embodiments,the composition is heated until it forms an Isomer 2 precursorcomposition, for example by forming greater than 50% Isomer 2. In someembodiments, the composition is heated at a temperature of about roomtemperature to about 100° C., preferably about 50° C. to about 80° C.,more preferably at about 60° C. Isomer 2 may subsequently be purified toobtain an Isomer 2 precursor composition comprising at least about 90%,at least about 95%, at least about 99%, or even at least about 99.5%Isomer 2. In some embodiments, the precursor composition is heated at atemperature of ≦50° C. until an Isomer 2 precursor compositioncomprising at least about 50%, at least about 60%, at least about 70%,at least about 80%, at least about 90%, at least about 95%, at leastabout 99%, or even at least about 99.5% Isomer 2 is obtained.

In some embodiments, an Isomer 1 and 2 precursor composition can beprepared by heating a composition consisting essentially of TTBA until adesired amount of Isomer 1 and 2 has formed in the composition. In someembodiments, the composition is heated until it comprises at least about20% of a combination of Isomer 1 and 2, thereby forming an Isomer 1 and2 precursor composition. In some embodiments, a TTBA composition isheated at a temperature of about room temperature to about 100° C.,preferably about 50° C. to about 80° C., more preferably at about 60° C.Isomer 1 and 2 may subsequently be purified to obtain an Isomer 1 and 2precursor composition comprising at least about 90%, at least about 95%,at least about 99%, or even at least about 99.5% of a combination ofIsomer 1 and Isomer 2. In some embodiments, the TTBA precursorcomposition is heated at a temperature of ≦50° C. until an Isomer 1 and2 precursor composition comprising at least about 20%, at least about30%, at least about 40%, at least about 50%, at least about 60%, atleast about 70%, at least about 80%, at least about 90%, at least about95%, at least about 99%, or even at least about 99.5% of a combinationof Isomer 1 and Isomer 2 is obtained. In some embodiments an Isomer 1and 2 precursor composition is prepared by combining Isomer 1 and Isomer2 compositions.

In some embodiments, a container containing an Isomer 1, Isomer 2 orIsomer 1 and 2 precursor composition is provided. The container may beconfigured to be utilized as a precursor source for a vapor depositionreactor. For example, the container may be configured to be fluidlyattached to a vapor deposition reactor.

In some embodiments, the container is stored at about 80° C. or less,more preferably about 50° C. or less, more preferably 25° C. or less, inorder to maintain the desired amount of Isomer 1 and/or Isomer 2 in thecomposition. In some embodiments, the desired amount is at least about50% Isomer 1, for example at least about 50, 60, 70, 75, 80, 85, 90, 91,92, 93, 94, 95, 98, 99 or 99.5% Isomer 1. In some embodiments, thedesired amount is at least about 50% Isomer 2, for example at leastabout 50, 60, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 98, 99 or 99.5%Isomer 2. In some embodiments the desired amount is at least about 20%of a combination of Isomer 1 and Isomer 2.

In some embodiments, the precursor composition in the containercomprises at least 20% of a combination of Isomer 1 and Isomer 2. Insome embodiments, the precursor composition in the container comprisesat least 50% of a combination of Isomer 1 and Isomer 2. In someembodiments, the precursor composition in the container comprises atleast 80% of a combination of Isomer 1 and Isomer 2. In someembodiments, the precursor composition in the container comprises acombination of Isomer 1 and Isomer 2 and does not comprise Isomer 3,orcomprises a trace amount of Isomer 3. In some embodiments, the precursorcomposition in the container comprises a combination of Isomer 1 andIsomer 2 and at most 5% Isomer 3. In some embodiments the precursorcomposition in the container comprises a combination of Isomer 1 andIsomer 2 and does not comprise TTBA or comprises a trace amount of TTBA.In some embodiments the precursor composition comprises a combination ofIsomer 1 and Isomer 2 and at most 5% Isomer 3.

In some embodiments, a vapor deposition reactor is provided comprising acontainer containing an Isomer 1, Isomer 2 or Isomer 1 and 2 precursorcomposition. In some embodiments, the container contains a compositioncomprising at least about 50% Isomer 1 or at least about 50% Isomer 2.In some embodiments, the container contains a composition comprising atleast about 70% Isomer 1 or at least about 70% Isomer 2. In someembodiments the container contains an Isomer 1 precursor compositioncomprising at least about 70%, at least about 80%, at least about 90%,at least about 95%, at least about 99%, or even at least about 99.5%Isomer 1. In some embodiments the container contains an Isomer 2precursor composition comprising at least about 50% Isomer 2. In someembodiments the container contains an Isomer 2 precursor compositioncomprising at least about 70%, at least about 80%, at least about 90%,at least about 95%, at least about 99%, or even at least about 99.5%Isomer 2. In some embodiments the container contains an Isomer 1 and 2precursor composition comprising at least about 20% of a combination ofIsomer 1 and 2, as described herein.

In some embodiments, the deposition reactor is configured to vaporizethe Isomer 1, Isomer 2 or Isomer 1 and 2 composition for depositing anAl-doped transition metal carbide thin film on a substrate in a reactionspace in the reactor. The reactor may be further configured to transportthe vaporized Isomer 1, Isomer 2 or Isomer 1 and 2composition to thereaction space. In some embodiments the reactor may comprise controlsset to provide a desired quantity of the vaporized Isomer 1, Isomer 2 orIsomer 1 and 2 composition to the reaction space at desired intervalsand for the desired amount of time.

In some embodiments, a vapor deposition reactor is also provided with acontainer containing an metal precursor composition, such as a titaniumprecursor composition. For example, a container may comprise a titaniumhalide precursor. The deposition reactor may be configured to vaporizethe metal precursor and transport the vaporized precursor to thereaction space. Controls may be provided that are set to provide adesired quantity of the vaporized metal precursor to the reaction spaceat a desired interval and for a desired amount of time.

Exemplary Deposition Methods

In some embodiments, a transition metal carbide thin film, for examplean aluminum-doped transition metal carbide thin film such as an Al-dopedtitanium carbide film is deposited by vapor deposition using a TTBAcomposition as disclosed herein, such as an Isomer 1, Isomer 2 or Isomer1 and 2 composition. However, the disclosed compositions can be used inany context in which an aluminum hydrocarbon compound may be desirable,and in particular may be used in any vapor depositions in which analuminum hydrocarbon compound may be suitable. Exemplary ALD and CVDprocesses are outlined generally below. However, other vapor depositionprocesses in which the TTBA compositions and in particular the Isomer 1,Isomer 2 or Isomer 1 and 2 compositions can be used will be apparent tothe skilled artisan.

Thus, in some embodiments, transition metal carbide thin films, forexample aluminum-doped transition metal carbide films such as Al-dopedtitanium carbide thin films can be deposited on a substrate using a anIsomer 1, Isomer 2 or Isomer 1 and 2 composition. In some embodiments,one or more transition metal halides can be used as the transition metalsource. In some embodiments a titanium halide precursor can be used as atitanium source to form titanium carbide films. In some embodiments, anIsomer 1, Isomer 2 or Isomer 1 and 2 composition is vaporized to form anIsomer 1, Isomer 2 or Isomer 1 and 2 reactant that is provided to areaction space comprising a substrate on which a titanium carbide filmis to be deposited. The substrate is also contacted with a vapor phasetransition metal reactant, such as a transition metal halide. In someembodiments the transition metal halide reactant is a titanium halidereactant. In some embodiments the metal halide reactant comprises atransition metal such as niobium or vanadium. The thin film can be anAl-doped transition metal carbide thin film and in some embodiments is atitanium carbide thin film and may be an Al-doped titanium carbide thinfilm (e.g., TiC or TiAlC thin film).

In some embodiments, the process of depositing a transition metalcarbide thin film such as an Al-doped titanium carbide thin film can bea chemical vapor deposition (CVD) process in which a substrate issimultaneously contacted with an Isomer 1, Isomer 2 or Isomer 1 and 2reactant and a transition metal reactant, for example a transition metalhalide such as a titanium halide reactant. In some embodiments, theprocess of depositing a transition metal carbide thin film such as anAl-doped titanium carbide thin film can be an atomic layer deposition(ALD) process in which a substrate is alternately and sequentiallycontacted with an Isomer 1, Isomer 2 or Isomer 1 and 2 reactant, formedby vaporizing an Isomer 1, Isomer 2 or Isomer 1 and 2 precursorcomposition, and a vapor phase transition metal reactant, such atransition metal halide. In some embodiments the transition metal halidereactant is a titanium halide reactant, such as TiCl₄.

Exemplary ALD Methods

ALD is based on typically self-limiting reactions, whereby sequentialand alternating pulses of reactants are used to deposit about one atomic(or molecular) monolayer of material per deposition cycle. Thedeposition conditions and precursors are typically selected to provideself-saturating reactions, such that an adsorbed layer of one reactantleaves a surface termination that is non-reactive with the gas phasereactants of the same reactant. The substrate is subsequently contactedwith a different reactant that reacts with the previous termination toenable continued deposition. Thus, each cycle of alternated pulsestypically leaves no more than about one monolayer of the desiredmaterial. However, as mentioned above, the skilled artisan willrecognize that in one or more ALD cycles more than one monolayer ofmaterial may be deposited, for example if some gas phase reactions occurdespite the alternating nature of the process.

In a typical ALD-type process for depositing metal carbide films, onedeposition cycle comprises exposing the substrate to a first reactant,removing any unreacted first reactant and reaction byproducts from thereaction space, exposing the substrate to a second reactant, followed bya second removal step. The first reactant is preferably a metalprecursor, in particular a transition metal precursor, such as atitanium precursor, and the second reactant is preferably a carburizing(or carbon-contributing) compound, such as the TTBA compositionsdescribed herein (although it is possible to begin the process witheither reactant).

The transition metal compound may comprise one or more transition metalsselected from the group consisting of, but not limited to, scandium(Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium(V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo),tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe),ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir),nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag),gold (Au), zinc (Zn), cadmium (Cd) and mercury (Hg). However, astitanium carbide films are exemplified herein, in such embodiments, themetal compound comprises titanium.

Typically, transition metal halide reactants, such as, e.g., TiCl₄, areused as metal precursors in ALD deposition.

A TTBA precursor composition is used as the aluminum reactant source. Inparticular, in some embodiments, an Isomer 1 precursor composition isused. As discussed above, an Isomer 1 precursor composition maycomprise, for example, about 50%, 60%, 70%, 80%, 90%, 95%, 99% or moreof Isomer 1. The Isomer 1 precursor composition may be provided in acontainer attached to the deposition reactor. The composition isvaporized and the Isomer 1 reactant vapor is provided to a reactionspace comprising the substrate.

In some embodiments, an Isomer 2 precursor composition is used. Asdiscussed above, an Isomer 2 precursor composition may comprise, forexample, about 50%, 60%, 70%, 80%, 90%, 95%, 99% or more Isomer 2. TheIsomer 2 precursor composition may be provided in a container attachedto the deposition reactor. The composition is vaporized and the Isomer 2reactant vapor is provided to a reaction space comprising the substrate.

In some embodiments, an Isomer 1 and Isomer 2 precursor composition isused . As discussed above, a combination of Isomer 1 and Isomer 2precursor composition may comprise at least 20%, at least 50%, or atleast 80% of a combination of Isomer 1 and Isomer 2 or only acombination of Isomer 1 and Isomer 2 and not Isomer 3. The Isomer 1 and2 precursor composition may be provided in a container attached to thedeposition reactor. The composition is vaporized and the combination ofIsomer 1 and 2 reactant vapor is provided to a reaction space comprisingthe substrate.

Precursors may be separated by inert gases, such as Ar, to preventgas-phase reactions between reactants and enable self-saturating surfacereactions. In some embodiments, however, the substrate may be moved toseparately contact a first metal reactant and a second Isomer 1, Isomer2 or Isomer 1 and 2 reactant. Because the reactions self-saturate,strict temperature control of the substrates and precise dosage controlof the precursors is not usually required. However, the substratetemperature is preferably such that an incident gas species does notcondense into monolayers nor decompose on the surface. Surplus chemicalsand reaction byproducts, if any, are removed from the substrate surface,such as by purging the reaction space or by moving the substrate, beforethe substrate is contacted with the next reactive chemical. Undesiredgaseous molecules can be effectively expelled from a reaction space withthe help of an inert purging gas. A vacuum pump may be used to assist inthe purging.

According to some embodiments, ALD-type processes are used to formtransition metal carbide thin films, for example Al-doped transitionmetal carbide thin films, such as Al-doped titanium carbide thin filmson a substrate, such as an integrated circuit workpiece. Preferably,each ALD cycle comprises two distinct deposition steps or phases. In afirst phase of the deposition cycle (“the metal phase”), the substratesurface on which deposition is desired is contacted with a firstreactant comprising a transition metal such as titanium (i.e., titaniumsource material or chemical) which chemisorbs onto the substratesurface, forming no more than about one monolayer of reactant species onthe surface of the substrate.

In some embodiments, the transition metal (e.g., titanium) sourcechemical, also referred to herein as the “transition metal compound” (orin some embodiments as the “titanium compound”), is a halide and theadsorbed monolayer is terminated with halogen ligands. In someembodiments, the titanium halide is TiCl₄.

Excess transition metal (e.g., titanium) source material and reactionbyproducts (if any) are removed from the substrate surface, e.g., bypurging with an inert gas. Excess transition metal source material andany reaction byproducts may be removed with the aid of a vacuumgenerated by a pumping system.

In a second phase of the deposition cycle (“carbon-contributing phase”),the substrate is contacted with a second Isomer 1, Isomer 2 or Isomer 1and 2 reactant, which reacts with the titanium-containing molecules lefton the substrate surface. Preferably, in the second phase carbon isincorporated into the film by the interaction of the second Isomer 1,Isomer 2 or Isomer 1 and 2 reactant with the monolayer left by thetransition metal (e.g., titanium) source material. In some embodiments,reaction between the second Isomer 1, Isomer 2 or Isomer 1 and 2reactant and the chemisorbed transition metal species produces atransition metal carbide thin film over the substrate, in someembodiments, an Al-doped transition metal carbide thin film. In someembodiments, reaction between the second Isomer 1, Isomer 2 or Isomer 1and 2 reactant and the chemisorbed titanium species produces an Al-dopedtitanium carbide thin film over the substrate.

Aluminum may be incorporated into the film in this second phase. In someembodiments, the aluminum content may vary from about 1% to about 30%,more preferably from about 6% to about 16%. In other embodiments, thealuminum content may be higher.

Excess second source chemical and reaction byproducts, if any, areremoved from the substrate surface, for example by a purging gas pulseand/or vacuum generated by a pumping system. Purging gas is preferablyany inert gas, such as, without limitation, argon (Ar) or helium (He). Aphase is generally considered to immediately follow another phase if apurge (i.e., purging gas pulse) or other reactant removal stepintervenes.

In some embodiments, the thin film deposition process is carried out ata temperature of less than about 500° C. In other embodiments, thedeposition process is carried out at a temperature of between about 300°C. to about 400° C. In other embodiments, the deposition process iscarried out at a temperature of about 300-350° C.

In some embodiments, the eWF of films deposited by ALD using an Isomer 1reactant and a metal halide, for example a titanium halide such asTiCl₄, can range from about 4.60 eV to about 4.30 eV. In someembodiments, the resistivity of such films can range from about 4.50 eVto about 4.20 eV.

The deposition rate of the thin film by ALD, which is typicallypresented as A/pulsing cycle, depends on a number of factors including,for example, on the number of available reactive surface sites or activesites on the surface and bulkiness of the chemisorbing molecules. Insome embodiments, the deposition rate of such films may range from about0.5 to about 5.0 Å/pulsing cycle. In some embodiments, the depositionrate can be about 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0Å/pulsing cycle.

The transition metal carbide thin films, such as Al-doped transitionmetal carbide thin film and in particular Al-doped titanium carbide thinfilms formed by the processes disclosed herein can be utilized in avariety of contexts, such as in the formation of electrode structures.One of skill in the art will recognize that the processes describedherein are applicable to many contexts, including fabrication of NMOStransistors including planar devices as well as multiple gatetransistors, such as FinFETs.

1.-20. canceled)
 21. A vapor deposition precursor composition comprising at least 50% Isomer 1, at least 50% Isomer 2, or greater than 20% of a combination of Isomer 1 and Isomer 2 of Al(tert-Bu)₃ (TTBA), wherein Isomer 1 has the formula Al(tert-Bu)₂(iso-Bu) and Isomer 2 has the formula Al(tert-Bu)(iso-Bu)₂.
 22. The composition of claim 21 comprising at least 70% Isomer
 1. 23. The composition of claim 21 comprising at least 80% Isomer
 1. 24. The composition of claim 21 comprising at least 70% Isomer
 2. 25. The composition of claim 21 comprising greater than 50% of a combination of Isomer 1 and Isomer
 2. 26. The composition of claim 21 comprising greater than 80% of a combination of Isomer 1 and Isomer
 2. 27. The composition of claim 21 comprising at least 80% Isomer
 2. 28. The composition of claim 21, wherein the composition comprises Al(tert-Bu)₃.
 29. The composition of claim 21, wherein the composition does not comprise Isomer
 3. 30. The composition of claim 21, additionally comprising Isomer 3 of Al(tert-Bu)₃, wherein Isomer 3 has the formula Al(iso-Bu)₃.
 31. The composition of claim 30, wherein the composition comprises at most 5% Isomer
 3. 32. A container configured to be attached to a deposition reactor, the container comprising a composition comprising at least 50% Isomer 1, at least 50% Isomer 2 or at least 20% of a combination of Isomer 1 and Isomer 2 of Al(tert-Bu)₃, wherein Isomer 1 has the formula Al(tert-Bu)₂(iso-Bu) and Isomer 2 has the formula Al(tert-Bu)(iso-Bu)₂.
 33. The container of claim 32, wherein the composition comprises at least 70% Isomer
 1. 34. The container of claim 32, wherein the composition comprises at least 90% Isomer
 1. 35. The container of claim 32, wherein the composition comprises at least 70% Isomer
 2. 36. The container of claim 32, wherein the composition comprises at least 90% Isomer
 2. 37. The container of claim 32, wherein the composition comprises at least 50% of a combination of Isomer 1 and Isomer
 2. 38. The container of claim 32, wherein the composition comprises at least 80% of a combination of Isomer 1 and Isomer
 2. 39. The container of claim 32, wherein the composition comprises only a combination of Isomer 1 and Isomer
 2. 40. The container of claim 32, wherein the composition additionally comprises Isomer 3 of Al(tert-Bu)₃, wherein Isomer 3 has the formula Al(iso-Bu)₃.
 41. The container of claim 40, wherein the composition comprises at most 5% Isomer
 3. 42.-51. (canceled) 